Auxetic sole with upper cabling

ABSTRACT

An article of footwear has an upper and a sole structure. The upper includes a base layer and one or more tensile strands. The sole structure includes an auxetic element operable to expand in two orthogonal horizontal directions in response to a tension applied in one of the directions. Each tensile strand has at least one end secured in fixed position relative to a peripheral region of the sole structure.

BACKGROUND

Articles of footwear generally include two primary elements: an upperand a sole structure. The upper is often formed from a plurality ofmaterial elements (e.g., textiles, polymer sheet layers, foam layers,leather, synthetic leather) that are stitched or adhesively bondedtogether to form a void on the interior of the footwear for comfortablyand securely receiving a foot. More particularly, the upper forms astructure that extends over instep and toe areas of the foot, alongmedial and lateral sides of the foot, and around a heel area of thefoot. This plurality of material elements may form a base layer of theupper. The upper may also incorporate a lacing system to adjust fit ofthe footwear, as well as permitting entry and removal of the foot fromthe void within the upper. In addition, the upper may include a tonguethat extends under the lacing system to enhance adjustability andcomfort of the footwear, and the upper may incorporate a heel counter.

The various material elements forming the upper impart differentproperties to different areas of the upper. For example, textileelements may provide breathability and may absorb moisture from thefoot, foam layers may compress to impart comfort, and leather may impartdurability and wear-resistance. As the number of material elementsincreases, the overall mass of the footwear may increase proportionally.The time and expense associated with transporting, stocking, cutting,and joining the material elements may also increase. Additionally, wastematerial from cutting and stitching processes may accumulate to agreater degree as the number of material elements incorporated into anupper increases. Moreover, products with a greater number of materialelements may be more difficult to recycle than products formed fromfewer material elements. By decreasing the number of material elements,therefore, the mass of the footwear and waste may be decreased, whileincreasing manufacturing efficiency and recyclability.

The sole structure is secured to a lower portion of the upper so as tobe positioned between the foot and the ground. In athletic footwear, forexample, the sole structure often includes a midsole and an outsole. Themidsole may be formed from a polymer foam material that attenuatesground reaction forces (i.e., provides cushioning) during walking,running, and other ambulatory activities. The midsole may also includefluid-filled chambers, plates, moderators, or other elements thatfurther attenuate forces, enhance stability, or influence the motions ofthe foot, for example. The outsole forms a ground-contacting element ofthe footwear and is usually fashioned from a durable and wear-resistantrubber material that includes texturing to impart traction. The solestructure may also include a sockliner positioned within the upper andproximal a lower surface of the foot to enhance footwear comfort.

SUMMARY

Within the sole structure of an article of footwear, the midsole, or theoutsole, or both may be formed to have an auxetic structure. Auxeticelements incorporated within sole structures may permit the footwear todynamically adjust its fit upon a wearer's foot in response to specificforces placed upon it, such as forces due to walking, running, athleticactivity, or other typical uses of the footwear. In addition, one ormore tensile strands separate from the material or materials of the baselayer may be incorporated into the upper. In an article incorporating anauxetic element in its sole structure, the additional incorporation oftensile strands in the upper of the footwear may advantageously permitlocalized tuning of the dynamic adjustment of fit imparted by theauxetic element.

In one aspect, an article of footwear includes an upper and a solestructure. The upper comprises a base layer and a tensile strand, thetensile strand having a first end and a second end. A portion of thetensile strand between the first end and the second end is separate fromthe material of the base layer and lies adjacent to a surface of thebase layer. The sole structure comprises an auxetic element with aplurality of apertures extending therethrough. The first end of thetensile strand has a fixed position relative to a peripheral region ofthe auxetic element.

In another aspect, an article of footwear includes a sole structure, abase layer, and a tensile strand. The sole structure includes an auxeticsole portion oriented along a plane. The plane extends in a firstdirection between a heel region and a forefoot region of the article offootwear, and extends in a second direction between a medial side and alateral side of the article of footwear. The auxetic sole portion has aplurality of apertures operable to change shape in response to either atension or a compression applied to the auxetic sole portion along theplane. The base layer is secured to a peripheral region of the solestructure. The tensile strand is separate from the material of the baselayer and has at least one end fixed in position relative to aperipheral region of the base layer.

In another aspect, an article of footwear includes a base layer, anauxetic sole element, and a plurality of tensile strands. The auxeticsole element extends along both a first direction and an orthogonalsecond direction of a plane, and comprises a plurality of first portionsjoined to each other by a plurality of second portions. Each of theplurality of tensile strands lies adjacent to a surface of the baselayer, and at least one end of each of the plurality of tensile strandshas a fixed position relative to a peripheral region of the auxetic soleelement. A tension applied to the auxetic sole element in either thefirst direction or the second direction induces the first portions torotate relative to one another and induces the auxetic sole element toexpand in both the first direction and the second direction.

Other systems, methods, features and advantages of the embodiments willbe, or will become, apparent to one of ordinary skill in the art uponexamination of the following figures and detailed description. It isintended that all such additional systems, methods, features andadvantages be included within this description and this summary, bewithin the scope of the embodiments, and be protected by the followingclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments can be better understood with reference to the followingdrawings and description. The components in the figures are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the embodiments. Moreover, in the figures, likereference numerals designate corresponding parts throughout thedifferent views.

FIG. 1 is a lateral side perspective view of an embodiment of an articleof footwear;

FIG. 2 is a lateral side elevational view of the article of footwear;

FIG. 3 is a medial side bottom perspective view of the article offootwear;

FIG. 4 is a medial side elevational view of the article of footwear;

FIG. 5 is a lateral side perspective view, an enlarged cut-away view,and a top cut-away view of the article of footwear;

FIG. 6 is a cross-sectional view of the article of footwear, as definedby section line 6-6 in FIG. 2;

FIG. 7 is a top plan view of the article of footwear;

FIG. 8 is a bottom plan view of the article of footwear;

FIG. 9 is a plan view of an alternate embodiment of an auxetic element;

FIG. 10 is a plan view of the element of FIG. 10 under tension in afirst direction (i.e., upon the application of an outwardly-directedforce);

FIG. 11 is a plan view of the element of FIG. 10 under tension in asecond direction;

FIG. 12 is a plan view of the element of FIG. 10 under compression in afirst direction (i.e., upon the application of an inwardly-directedforce);

FIG. 13 is a plan view of the element of FIG. 10 under compression in asecond direction;

FIGS. 14-15 are plan views of a portion of the element of FIG. 10;

FIGS. 16-17 are plan views of the portion of the element of FIG. 10under an applied tension;

FIGS. 18-19 are plan views of the portion of the element of FIG. 10under an applied compression;

FIGS. 20-21 are lateral side perspective views, enlarged cut-away views,and top cut-away views of an alternate embodiment of the article offootwear being used by a wearer;

FIGS. 22-25 are lateral side perspective views, enlarged cut-away views,and top cut-away views corresponding with FIG. 5 and depicting thearticle of footwear of FIGS. 1-8 being used by a wearer;

FIGS. 26-27 are lateral side elevational views corresponding with FIG. 2and depicting further configurations of the footwear;

FIGS. 28-29 are cross-sectional views corresponding with FIG. 6 anddepicting further configurations of the footwear;

FIG. 30 is a cross-sectional view corresponding with FIG. 7 anddepicting a further configuration of the footwear;

FIGS. 31-35 are bottom plan views corresponding with FIG. 9 anddepicting further configurations of the footwear;

FIG. 36 is a plan view corresponding with FIG. 10 and depicting afurther configuration of the auxetic element;

FIG. 37 is a lateral side perspective view of a further configuration ofthe footwear of FIG. 1;

FIG. 38 is a lateral side elevational view of the article of footwear ofFIG. 38;

FIG. 39 is medial side bottom perspective view of the article offootwear of FIG. 38;

FIG. 40 is a medial side elevational view of the article of footwear ofFIG. 38; and

FIG. 41 is a top plan view of the article of footwear of FIG. 38.

DETAILED DESCRIPTION

The following discussion and accompanying figures disclose articles offootwear having uppers that include tensile strands and sole structuresthat include auxetic elements. The article of footwear is disclosed ashaving a general configuration suitable for walking or running. Conceptsassociated with the footwear, including the upper, may also be appliedto a variety of other athletic footwear types, including baseball shoes,basketball shoes, cross-training shoes, cycling shoes, football shoes,tennis shoes, soccer shoes, and hiking boots, for example. The conceptsmay also be applied to footwear types that are generally considered tobe non-athletic, including dress shoes, loafers, sandals, and workboots. The concepts disclosed herein apply, therefore, to a wide varietyof footwear types.

General Footwear Structure

An article of footwear 10 is depicted in FIGS. 1-8 as including an upper200 and a sole structure 300. For reference purposes, footwear 10 may bedivided into three general regions: a forefoot region 11, a midfootregion 12, and a heel region 13, as shown in FIGS. 2 and 4. Forefootregion 11 generally includes portions of footwear 10 corresponding withthe toes and the joints connecting the metatarsals with the phalanges.Midfoot region 12 generally includes portions of footwear 10corresponding with the arch area of the foot. Heel region 13 generallyincludes portions of footwear 10 corresponding with rear portions of thefoot, including the calcaneus bone.

Footwear 10 also includes a medial side 14 and a lateral side 15. Medialside 14 and lateral side 15 and extend through each of forefoot region11, midfoot region 12, and heel region 13 and correspond with oppositesides of footwear 10.

Forefoot region 11, midfoot region 12, heel region 13, medial side 14,and lateral side 15 are not intended to demarcate precise areas offootwear 10. Rather, they are intended to represent general areas offootwear 10 to aid in the following discussion. In addition to beingapplied to footwear 10, forefoot region 11, midfoot region 12, heelregion 13, medial side 14, and lateral side 15 may also be applied toupper 200, sole structure 300, and individual elements thereof.

The primary elements of upper 200 are a base layer 210 and a pluralityof tensile strands 230. A variety of material elements or othercomponents may be incorporated into base layer 210. Base layer 210 maybe formed from one or more of a plurality of material elements (e.g.,textiles, polymer sheets, foam layers, leather, synthetic leather) thatare stitched or bonded together to form a void within footwear 10 forreceiving and securing a foot of a wearer relative to sole structure300. The void is shaped to accommodate the foot and extends along thelateral side of the foot, along the medial side of the foot, over thefoot, around the heel, and under the foot.

Access to the void is provided by an ankle opening 202 located in atleast heel region 13. A lace 204 extends through various lace apertures227 in base layer 210 and permits the wearer to modify dimensions ofupper 200 to accommodate the proportions of the foot. More particularly,lace 204 permits the wearer to tighten upper 200 around the foot, andlace 204 permits the wearer to loosen upper 200 to facilitate entry andremoval of the foot from the void (i.e., through ankle opening 202). Inaddition, upper 200 includes a tongue 208 that extends between theinterior void and lace 204 to enhance the comfort of footwear 10.

As an alternative to lace apertures 207, upper 200 may include otherlace-receiving elements, such as loops, eyelets, and D-rings. In someconfigurations, upper 200 may incorporate a heel counter that limitsheel movement in heel region 13 or a wear-resistant toe guard located inforefoot region 11.

Both medial side 14 and lateral side 15 and of upper 200 are depicted asincorporating various tensile strands 230 having first ends 231, secondends 232, and middle portions 233 extending between first ends 231 andsecond ends 232. Although depicted as including five tensile strands 230on each of medial side 14 and lateral side 15 of upper 200, each ofmedial side 14 and lateral side 15 may include any number of tensilestrands 230. In some configurations, either medial side 14 or lateralside 15 may not include any tensile strands 230. The number of tensilestrands 230 incorporated into footwear 10 may accordingly varysignificantly.

In some embodiments, tensile strands may have at least a minimal lengththereby ensuring that the tensile strands provide support between (orthrough) two or more distinct regions of an article. As depicted, middleportions 233 of tensile strands 230 have lengths of at least 3 cm, andtensile strands 230 accordingly extend over distances of at least 3 cm.In various configurations of footwear 10, middle portions 233 may havelengths of at least 5 cm or at least 10 cm, and tensile strands 230 mayextend over distances of at least 5 cm or at least 10 cm, respectively.Although first ends 231 and second ends 232 are depicted as beingpositioned at different locations spaced from each other by a distanceof between 1 cm and 5 cm, first ends 231 and second ends 232 of at leastsome of tensile strands 230 may be spaced from each other by distancesless than 1 cm, or distances greater than 5 cm.

The material of tensile strands 230 is separate from the material ofbase layer 210. Moreover, while tensile strands 230 are secured tofootwear 10 at first ends 231 and second ends 232, and while middleportions 233 lie adjacent to an outer surface 211 of base layer 210,part or all of middle portions 233 may be unattached to or unbonded tobase layer 210 in some configurations of footwear 10. That is, part orall of middle portions 233 may be unsecured to base layer 210 and mayaccordingly be free to move relative to base layer 210.

Tensile strands 230 of footwear 10 generally extend between a centralregion or lace aperture region 226 of base layer 210 (i.e., the regionwhere lace apertures 227 or other lace-receiving elements are located)and a peripheral region 222 of the base layer (i.e., the region at whichupper 200 joins with sole structure 300). More particularly, tensilestrands 230 extend from lace aperture region 226 to peripheral region222 of base layer 210, or to peripheral region 322 of sole structure300, or both. Base layer 210 may additionally have a middle region 224extending between peripheral region 222 and lace aperture region 226.

For example, FIGS. 1-4 show each of tensile strands 230 as extendingbetween peripheral region 322 of sole structure 300 and an area proximalto a lace aperture 227 in lace aperture region 226. First ends 231 andsecond ends 232 of tensile strands 230 are secured in fixed positionsrelative to peripheral region 322 of sole structure 300, and middleportions 233 of tensile strands 230 extend around lace apertures 227.

In some configurations of footwear 10, at least some of first ends 231and second ends 232 may be secured directly to peripheral region 322 ofsole structure 300, such as by being adhesively bonded or physicallycoupled to peripheral region 322. In other configurations of footwear10, at least some of first ends 231 and second ends 232 may be securedindirectly to peripheral region 322 of sole structure 300. For example,first ends 231 and second ends 232 may be secured directly to peripheralregion 222 of base layer 210, and peripheral region 222 may in turn bedirectly secured to peripheral region 322 of sole structure 300. In suchconfigurations, although not directly secured to peripheral region 322of sole structure 300, first ends 231 and second ends 232 may still besecured to have a fixed position relative to peripheral region 322. Instill further configurations, at least some of first ends 231 and secondends 232 may be bonded to or otherwise secured to both peripheral region222 of base layer 210 and peripheral region 322 of sole structure 300.In various configurations, first ends 231 and second ends 232 may beeither secured either directly or indirectly to peripheral region 222,or peripheral region 322, or both, and may thus be fixed in positionrelative to either peripheral region 222, or peripheral region 322, orboth.

Peripheral region 222 of upper 200 is depicted in FIG. 5 as beingsecured to peripheral region 322 of sole structure 300. The primaryelements of sole structure 300 are a sockliner 206 and an auxeticelement 330. Sockliner 206 is located within upper 200 and is positionedto extend under a lower surface of the foot. Auxetic element 330 extendsbetween the foot and the ground when footwear 10 is worn, and isdepicted as forming a ground-contacting surface of footwear 10.Accordingly, in some embodiments, auxetic element 330 may form anoutsole element of footwear 10.

As best shown in FIGS. 3 and 5, auxetic element 330 has a first surface331, which is secured to a lower part of outer surface 211 of upper 200,and a second surface 332 which forms a ground-contacting surface offootwear 10. First surface 331 may accordingly be an upper surface ofauxetic element 330, while second surface 332 may be a lower surface ofauxetic element 330. A peripheral region 342 of auxetic element 330extends to a peripheral region 322 of sole structure 300, while acentral region 346 of auxetic element 330 is positioned at a centralregion 326 of sole structure 300. Put another way, auxetic element 330is depicted in FIGS. 1-8 as spanning an entirety of a horizontal extentof sole structure 300, from forefoot region 11 to heel region 13, andfrom medial side 14 to lateral side 15.

Across this span, auxetic element 330 has a plurality of first portions351, a plurality of second portions 352 joining first portions 351, andapertures 360 surrounded by first portions 351 and second portions 352.Apertures 360 extend from first surface 331 to second surface 332, andcompletely through auxetic element 330 in a vertical direction. Firstportions 351, second portions 352, and apertures 360 advantageouslyprovide auxetic element 330 with an auxetic structure.

Auxetic Element and Auxetic Structure

As used herein, the term “auxetic structure” generally refers to astructure that, when it is placed under tension in a first direction,increases its dimensions in a direction that is orthogonal to the firstdirection. Such auxetic structures may be characterized as having anegative Poisson's ratio. Although such structures will generally haveat least a monotonic relationship between the applied tension and theincrease in the dimension orthogonal to the direction of the tension,that relationship need not be proportional or linear, and in generalneed only increase in response to increased tension.

FIG. 9 depicts an alternate configuration of auxetic element 330,separate from footwear 10. The structural features of auxetic element330 include: first portions 351 of the material of auxetic element 330,which have polygonal shapes, or more specifically triangular shapes;second portions 352 of the material of auxetic element 330, which joinadjacent first portions 351; and apertures 360 between first portions351 and second portions 352, which have polygonal shapes, or morespecifically shapes of re-entrant triangles, or three-pointed stars.

First portions 351, second portions 352, and apertures 360 are arrangedin a regular geometric pattern. More specifically, first portions 351,second portions 352, and apertures 360 are arranged in a regularhexagonal tessellation. As a result, the pattern of the structure ofauxetic element 330 may be reduced to a pattern contained within onehexagon laid adjacent to itself repeatedly.

In FIG. 9, for example, hexagon 380 surrounds a part of auxetic element330 which, if laid adjacent to itself repeatedly, would produce thepattern of auxetic element 330 as a whole. Hexagon 380 may accordinglybe considered a unit of the regular hexagonal tessellation of auxeticelement 330. As depicted, hexagon 380 contains an alternating sequenceof six first portions 351 and six second portions 352 that surround anddefine the boundary of one aperture 360. A person of ordinary skill inthe art will recognize that other hexagonal parts of auxetic element 330could be similarly repeated to produce the pattern of auxetic element330 as a whole.

Due to the structure of first portions 351, second portions 352, andapertures 360, auxetic element 330 has advantageous properties inresponse to forces applied to it. FIGS. 10 and 11 depict auxetic element330 under an applied tension (i.e., an outwardly-directed or “pulling”force). FIG. 10 shows auxetic element 330 under application of a tension511 being applied in a first direction (depicted using solid, closedarrows). In response to tension 511 in the first direction, auxeticelement 330 exhibits an expansion 521 in the first direction (depictedusing open arrows). However, in addition to expansion 521, auxeticelement 330 also exhibits an expansion 522 in a second directionorthogonal to the first direction (also depicted using open arrows). Inother words, when auxetic element 330 is pulled outward in onedirection, it expands outward in both that direction and another,perpendicular direction.

Although the first direction is depicted as being between the left-handand right-hand sides of the figure, other first directions could bebetween any two opposite points on auxetic element 330. Similarly,although the second direction is depicted as being between the top andbottom of the figure, second directions could be orthogonal to otherfirst directions.

FIG. 11 similarly depicts the application of a tension 512 in the seconddirection to auxetic element 330. Tension 512 is being applied in adirection orthogonal (or perpendicular) to the direction of tension 511in FIG. 10. As FIG. 11 shows, auxetic element 330 responds to tension512 by exhibiting not only an expansion 522 in the second direction, butalso an expansion 521 in the first direction. In other words, as seen inFIGS. 10 and 11, a tension applied to auxetic element 330 in onedirection induces auxetic element 330 to expand outward in both thatdirection and another, perpendicular direction.

In contrast with FIGS. 10 and 11, FIGS. 12 and 13 depict thecomplementary behavior of auxetic element 330 under an appliedcompression (i.e., an inwardly-directed or “pushing” force). As depictedin FIG. 14, upon application of a compression 531 in the first direction(depicted using solid, closed arrows), auxetic element 330 exhibits botha contraction 541 in the first direction and a contraction 542 in thesecond direction (depicted using open arrows). Similarly, as depicted inFIG. 13, upon application of a compression 532 in the second direction,auxetic element 330 exhibits both contraction 541 in the first directionand contraction 542 in the second direction. That is, when auxeticelement is compressed in one direction, it contracts inward in both thatdirection and another, perpendicular direction. (As with FIGS. 10 and11, although the first direction is depicted as being between theleft-hand and right-hand sides and the second direction is depicted asbeing between the top and bottom, other first directions could bebetween any two opposite points on auxetic element 330, and seconddirections could be orthogonal to any other first directions.)

FIGS. 14 and 15 depict a portion of auxetic element 330 in greaterdetail. The depicted portion of auxetic element 330 includes six firstportions 351 and six second portions 352 surrounding and defining anaperture 360 (as well as parts of the surrounding first portions 351,second portions 352, and apertures 360). As shown, the reentranttriangular shapes of apertures 360 have three sides 361, which definethree inwardly-pointing vertices 362 associated with threeoutwardly-opening or reentrant angles 363. The reentrant triangularshapes of apertures 360 also have three outwardly-pointing vertices orpoints 364 associated with three inwardly-opening angles 365. As shownin FIGS. 14 and 15, each aperture 360 accordingly has a central portion366 between three inwardly-pointing vertices 362, and three radialportions 367 between points 364 and inwardly-pointing vertices 362.

Apertures 360 are accordingly six-sided polygons, having threeoutwardly-opening angles (on the “sides” of their reentrant-triangleshapes) and three inwardly-opening angles (on the “points” of theirreentrant-triangle shapes). The three sides 361 of the reentranttriangles of apertures 360 have reentrant angles 363 of between about100 degrees and about 170 degrees when auxetic element 330 is not undertension (as depicted in FIGS. 14 and 15).

Each first portion 351 has a center 353 located at a central point oftheir triangular shapes, and each second portion 352 joins two firstportions 351. In addition, the sides of the triangular shapes of firstportions 351 correspond to segments of first portions 351 betweenadjacent second portions 352. With respect to those segments of firstportions 351, each second portion 352 is connected to its nearestneighboring second portions 352 by segments of the two first portions351 that it joins. Each second portion 352 accordingly has four nearestsecond portions 352 to which it is connected by sides of the two firstportions 351 that it joins (at least at portions of auxetic element 330spaced inward from its edges).

Auxetic element 330 thus contains a network of second portions 352 whichare connected to each other by segments of first portions 351 thatcorrespond to sides of the triangular shapes of first portions 351. Anytwo second portions 352 spaced apart from each other within auxeticelement 330 are connected by a path between them comprising sides offirst portions 351. FIG. 15 depicts an exemplary path 370 comprisingsegments 371, which are at angles 372 with respect to each other.

Due to the structure of auxetic element 330, first portions 351 areoperable to rotate in response to an applied force. At the same time,due to the structure of auxetic element 330, apertures 360 arecorrespondingly operable to change shape in response to an appliedforce. In FIGS. 16 and 17, the portion of auxetic element 330 depictedin FIGS. 14 and 15 is shown under application of an outwardly-directed“pulling” force or tension 510. Under tension 510, first portions 351rotate around their centers 353. More particularly, as shown in FIG. 16,any two nearest-neighboring first portions 351 within auxetic element330 (i.e. two first portions 351 joined by a second portion 352) rotatearound their centers 353 in opposite directions, one in a clockwisedirection, and the other in a counter-clockwise direction.

At the same time, as shown in FIG. 17, any two nearest-neighboring firstportions 351 rotate in opposite directions around the second portion 352that joins them (again, one in a clockwise direction, and the other in acounter-clockwise direction). In the course of this rotation,outwardly-opening angles 363 and inwardly-opening angles 365 increase inmagnitude, central portion 366 and radial portions 367 increase in area,and aperture 360 increases in area and changes shape.

FIG. 17 also depicts exemplary path 370 as being made more straightunder the application of tension 510. Angles 372 between segments 371increase in magnitude, and accordingly, for non-neighboring secondportions 352 connected by path 370, a distance between those secondportions 352 also increases. The application of a tension between twosecond portions 352 may thus straighten a path between the secondportions 352, and may induce adjoining first portions 351 to rotate,which may in turn straighten orthogonal paths between othernon-neighboring second portions 352 and thereby increase a distancebetween those other second portions 352.

In contrast, FIGS. 18 and 19 depict auxetic element 330 underapplication of an inwardly-directed “pushing” force or compression 530.Under application of compression 530, first portions 351 rotate aroundtheir centers 353, but in directions opposite to their direction ofrotation under application of tension 510. In other words, firstportions 351 that rotate around their centers 353 in a clockwisedirection when under tension rotate around their centers 353 in acounter-clockwise direction when under compression. Similarly, firstportions 351 that rotate around their centers in a counter-clockwisedirection when under tension rotate around their centers 353 in aclockwise direction when under compression.

At the same time, as shown in FIG. 19, nearest-neighboring firstportions 351 rotate around the second portion 352 that joins them underapplication of compression 530, but in directions opposite to theirdirections of rotation under application of tension 510. First portions351 that rotate around adjoining second portions 352 in a clockwisedirection when under tension instead rotate counter-clockwise aroundthose adjoining second portions 352 under compression, while firstportions 351 that rotate counter-clockwise around adjoining secondportions 352 when under tension instead rotate clockwise around thoseadjoining second portions 352 under compression. Meanwhile,outwardly-opening angles 363 and inwardly-opening angles 365 decrease inmagnitude, and central portion 366 and radial portions 367 decrease inarea. In some configurations of auxetic element 330, upon application ofa sufficient compression, one or more of angles 363 may decrease to zeromagnitude, and one or more of portions 366 and 367 may decrease to zeroin area.

In FIG. 19, angles 372 between segments 371 are depicted as decreasingin magnitude, making path 370 less straight under the application ofcompression 530. Accordingly, for non-neighboring second portions 352connected by path 370, a distance between those second portions 352 alsodecreases. Thus, the application of a compression between two secondportions 352 may make a path between the second portions 352 lessstraight; in turn, this may induce a rotation in adjoining firstportions 351, which may make an orthogonal path between other secondportions 352 less straight and may thereby decrease a distance betweenthose other second portions 352.

Auxetic Elements and Tensile Strands

Returning now to FIGS. 1-8, and with additional reference to FIGS.20-25, due to the auxetic structure of element 330, footwear 10 mayexhibit advantageous characteristics during use. For example, asdepicted in FIGS. 1-8, auxetic element 330 is oriented along a planeextending in a first horizontal direction between forefoot region 11 andheel region 13, and extending in a second horizontal direction betweenmedial side 14 and lateral side 15 of footwear 10. A tension applied tosole structure 300 in either the forefoot-heel direction (e.g., thelongitudinal direction) or the medial-lateral direction will accordinglyinduce an expansion of auxetic element 330 along the plane in both theforefoot-heel direction and the medial-lateral direction.

Either at the beginning of a step (i.e., when the foot and footwear 10initially contact the ground), or at the end of a step (i.e., when thefoot and footwear 10 leave the ground), or at some time in between, awearer's foot may move within footwear 10, or a force having at leastsome forefoot-heel component or medial-lateral component may otherwisepush against footwear 10, or against portions of footwear 10. This mayplace an outwardly-directed force (i.e., a tension) or aninwardly-directed force (i.e., a compression) upon one or more localportions of auxetic element 330.

The force placed upon auxetic element 330 may then cause at least alocal expansion or contraction in the structure of auxetic element 330.A localized tension or compression caused in the course of the wearer'suse of footwear 10 may in turn induce a rotation in at least some firstportions 351 near the corresponding portion of auxetic element 330, andthe rotation of those first portions 351 may cause the localizedexpansion or localized contraction to propagate at least partiallythrough auxetic element 330.

Meanwhile, as discussed above, tensile strands 230 may be secured infixed position relative to specific locations along peripheral region322 of sole structure 300, such as by being directly secured toperipheral region 322. Moreover, peripheral region 342 of auxeticelement 330 may extend to peripheral region 322 of sole structure 300and may span an entirety of a horizontal extent of sole structure 300.Because of this, tensile strands 230 may be indirectly or directlysecured to specific locations along peripheral region 342, and may thusbe secured in fixed position relative to specific locations along ahorizontal extent of peripheral region 322 of sole structure 300.

However, tensile strands 230 may also be designed to be less stretchablethan base layer 210. Base layer 210 may exhibit a first degree ofexpansion under a tension applied to upper 200, and tensile strands 230may exhibit a second degree of expansion under the same tension, and thefirst degree of expansion may be greater than the second degree ofexpansion. Alternatively, in response to the same applied tension,tensile strands 230 may exhibit a degree of linear stretch that is lessthan the degree of linear stretch exhibited by portions of base layer210 adjacent to tensile strands 230. For example, base layer 210 mayexhibit a greater degree of stretch between two locations than a tensilestrand 230 having a first end 231 and a second end 232 secured to thosetwo locations. The expansion of base layer 210 between two suchlocations may accordingly be limited more by the properties of tensilestrands 230 than by the properties of base layer 210.

As a result, specific advantages may arise from the incorporation oftensile strands 230 between peripheral region 342 of auxetic element 330and other locations of footwear 10. The use of tensile strands 230 maypermit upper 200 to limit the transmission of tension to specificlocations along auxetic element 330. This may facilitate the auxeticexpansion (and contraction) of sole structure 300 with respect tospecific, localized areas of auxetic element 330, which may in turnpermit tuning of the localized dynamic adjustment of fit in response toan applied tension (or compression). The configurations of tensilestrands 230 and auxetic element 330 may thus be tuned to advantageouslycause footwear 10 to dynamically adjust its fit upon the wearer's footin specific ways in response to specific forces placed upon it. Forexample, FIG. 20 depicts an alternate embodiment of footwear 10 around afoot 1000 of a wearer. In this alternate embodiment, upper 200 does notinclude tensile strands, and sole structure 300 does not include anauxetic element. FIG. 20 depicts footwear 10 while the wearer is in astatic, standing position.

In FIG. 21, the wearer is in motion, and has braced footwear 10 againstthe ground in order to quickly change direction, as part of a lateral“banking” or “cutting” movement. As a result, foot 1000 is pushingoutward on lateral side 15 of upper 200. In response, in a forefootregion and a midfoot region of footwear 10, lateral side 15 is pushedout over sole structure 300, and a gap has been left between foot 1000and an inner surface of upper 200 on medial side 14.

In contrast, FIG. 22 depicts the embodiment of footwear 10 of FIGS. 1-8around foot 1000. The wearer begins in a static, standing position inFIG. 22. In FIG. 23, the wearer has just placed footwear 10 against theground as part of a lateral “banking” or “cutting” movement, and foot1000 has started to press against lateral side 15 of upper 200.

In FIG. 24, the wearer is in the middle of the “banking” or “cutting”movement, and has just changed the direction of movement. However, incontrast with the alternate embodiment of footwear depicted in FIGS. 20and 21, foot 1000 in FIG. 23 has not extended outward beyond the solestructure. Instead, tensile strands 230 have applied tension to specificlocations along peripheral region 342 of auxetic element 330, causingauxetic element 330 to exhibit a localized auxetic expansion inresponse. Auxetic element 330 has extended outward and slightly upward,remaining under foot 1000. Footwear 10 is accordingly kept betterconformed to the foot of the wearer.

In another example, FIG. 25 depicts the embodiment of footwear 10 ofFIGS. 1-8 as used by a wearer taking a step. In the course of taking thestep, footwear 10 and sole structure 300 have bent at an area betweenforefoot region 11 and midfoot region 12. This causes auxetic element330 to bend in a corresponding manner, applying a tension to auxeticelement 330 in a forefoot-heel direction. The tension applied to auxeticelement 330 in turn induces an expansion of auxetic element 330 in aforefoot-heel direction, and due to the auxetic nature of element 330,the expansion in the forefoot-heel direction in turn induces acorresponding expansion in a medial-lateral direction.

More specifically, the tension applied to the localized area of solestructure 300 may induce first portions 351 in that area to rotate(around second portions 352 that join them, and around their centers353), may induce distances between second portions 352 in that area toincrease, and may induce apertures 360 in that area to increase in areaand change shape. Tensile strands 230 may then pull peripheral region322 of sole structure 300 and peripheral region 342 of auxetic element330 upward. Under tension from tensile strands 230, sole structure 300is accordingly induced to wrap upward along the sides of footwear 10around the area between forefoot region 11 and midfoot region 12,keeping footwear 10 better conformed to the foot of the wearer.

Further Configurations

As discussed above and as depicted in FIGS. 1-8, tensile strands 230have first ends 231 and second ends 232 that are fixed in positionrelative to peripheral region 322 of sole structure 300. In otherconfigurations, however, first ends 231 and second ends 232 may be fixedin other positions. For example, FIG. 26 depicts a configuration offootwear 10 in which first ends 231 are fixed in position relative toperipheral region 322 of sole structure 300, but second ends 232 arefixed in position relative to lace apertures 227 in lace aperture region226 of base layer 210. That is, instead of middle portions 233 oftensile strands 230 extending around lace apertures 227, at least somefirst ends 231 and second ends 232 of tensile strands 230 may be securedto areas proximal to lace apertures 227.

Furthermore, in some configurations, a tensile strand 230 may have amiddle portions 233 fixed in position relative to a lace aperture 227,or two complementary tensile strands 230 may each have a first end 231secured to have a fixed position relative to peripheral region 322 ofsole structure 300, and may each have a second end 232 secured to have afixed position relative to a lace aperture 227. Either configuration mayhave advantages similar to configurations in which a tensile strand 230has a first end 231 and a second end 232 fixed in position relative toperipheral region 322 and a middle portion 233 extending around a laceaperture 227.

In another exemplary embodiment, as depicted in FIG. 27, at least sometensile strands 230 may not span an entire distance between peripheralregion 222 and lace aperture region 226. In such configurations, atleast some of tensile strands 230 may have a first end 231 secured infixed position relative to peripheral region 322 of sole structure 300,and may have a second end 232 secured to middle region 224 of base layer210.

Tensile strands 230 are depicted in FIGS. 1-8 as lying adjacent to anouter surface 211 of base layer 210. In other configurations, tensilestrands 230 may be otherwise situated relative to base layer 210. InFIG. 28 for example, base layer 210 comprises a first layer 213 ofmaterial at outer surface 211 of base layer 210, and a second layer ofmaterial 214 at inner surface 212 of base layer 210. Tensile strand 230is situated between first layer 213 and second layer 214, and is atleast partially enveloped by first layer 213. Alternatively, as depictedin FIG. 29, tensile strands 230 may be embedded within a material ofbase layer 210.

Tensile strands 230 may accordingly have the configuration of thethreads of the articles of footwear disclosed in U.S. Pat. No.7,870,681, or the strands of the articles of footwear disclosed in U.S.Pat. No. 8,132,340, or the strands of the articles of footwear disclosedin U.S. Pat. No. 8,631,589, or the yarns of the articles of footweardisclosed in U.S. Pat. No. 8,490,299, such prior U.S. Patents beingentirely incorporated herein by reference. Moreover, base layer 210 mayhave the configuration of the knitted components of U.S. Pat. No.8,490,299. Also, in some embodiments, base layer 210 can include one ormore auxetic portions, allowing one or more portions of upper 200 tostretch and deform auxetically. For example, in some embodiments, baselayer 210 and/or other aspects of footwear 10 can include featuresdisclosed in U.S. patent application Ser. No. 14/469,973, entitledKnitted Component Having Tensile Strand For Adjusting Auxetic Portion,which was co-filed with the present application on Aug. 27, 2014, hedisclosure of which is incorporated by reference in its entirety.

FIGS. 1-8 depict auxetic element 330 as comprising those portions ofsole structure 300 outside of sockliner 206, and as forming aground-contacting surface of footwear 10. In other words, auxeticelement 330 is depicted as forming an entirety of sole structure 300outside of base layer 210. However, other configurations of solestructure 300 are possible.

For example, with reference to FIG. 30, sole structure 300 may include anumber of sole elements, such as a midsole element 301 and an outsoleelement 302. Midsole element 301 may be formed from a compressiblepolymer foam element (e.g., a polyurethane or ethylvinylacetate foam)that attenuates ground reaction forces (i.e., provides cushioning) whencompressed between the foot and the ground during walking, running, orother ambulatory activities. Outsole element 302 may be secured to alower surface of midsole element 301 and may be formed from awear-resistant rubber material that is textured to impart traction.Auxetic element 330 may therefore include portions of midsole element301 and outsole element 302.

In some configurations, auxetic element 330 may be either a midsoleelement having an auxetic structure or an outsole element having anauxetic structure. Auxetic element 330 may accordingly be an auxeticsole element, and may include either an auxetic midsole element, andauxetic outsole element, or both.

Although auxetic element 330 is depicted in FIGS. 1-8 as extendingacross an entirety of sole structure 300, auxetic element 330 may havean alternate span across sole structure 300. In various configurations,auxetic element 330 may extend across one or more portions of solestructure 300, but may be absent in one or more other portions of solestructure 300. Accordingly, one or more portions of sole structure 300may be auxetic portions having an auxetic structure, and one or moreportions may be non-auxetic portions without an auxetic structure.

FIGS. 31-36 depict exemplary configurations of footwear 10 in whichauxetic element 330 has an alternate span. For example, FIG. 31 depictsa configuration of sole structure 300 having an auxetic portion inforefoot region 11, an auxetic portion in heel region 13, and anon-auxetic portion 430 in between, in midfoot region 12. Accordingly,footwear 10 has an auxetic element 1330 in forefoot region 11, andanother auxetic element 2330 in heel region 13. In contrast, solestructure 300 is depicted in FIG. 32 as having a non-auxetic portion1430 in forefoot region 11, a non-auxetic portion 2430 in heel region13, and an auxetic portion in midfoot region 12, and footwear 10accordingly has only one auxetic element 330.

In FIG. 33, sole structure 300 is depicted as having an auxetic portion1330 on medial side 14 and an auxetic portion 2330 on lateral side 15,separated by a non-auxetic portion running through central region 326.In this configuration, footwear 10 has two auxetic element 330.Similarly, in FIG. 34, sole structure 300 is depicted as having anauxetic structure on both medial side 14 and lateral side 15, but theauxetic structure continues through peripheral region 322 in bothforefoot region 11 and heel region 13. In other words, an outsideportion of sole structure 300 has an auxetic structure. Footwear 10 thushas one auxetic element 330, spanning peripheral region 322. In contrastto FIG. 34, FIG. 35 depicts an inside portion of sole structure 300 ashaving an auxetic structure, and thus footwear 10 has one auxeticelement 330 spanning central region 326.

So, as depicted in FIG. 30, sole structure 300 may have various soleelements, such as a midsole element 301 or an outsole element 302, andeither or both of those sole elements may be auxetic sole elements. Atthe same time, as depicted in FIGS. 31-36, sole structure 300 may havevarious portions, one or more of which may be auxetic, and one or moreof which may be non-auxetic. Sole structure 300 may accordingly have amidsole element 301 or an outsole element 302, either one of which mayhave both auxetic portions and non-auxetic portions, and may thereforehave a variety of auxetic elements 330.

FIGS. 1-8 depict auxetic element 330 as having apertures that aresubstantially the same size and substantially the same shape whenelement 330 is not under tension. In other configurations, however, asize of apertures 360, or a shape of apertures 360, or both may varyacross auxetic element 330.

Although FIGS. 1-8 and 9-19 depict auxetic element 330 as having anauxetic structure comprised of triangular first portions 351 joined bysecond portions 352 and surrounding apertures 360 withreentrant-triangle shapes, auxetic element 330 may have other auxeticstructures. FIG. 36 depicts an alternate configuration of the auxeticstructure of auxetic element 330, in which rectangular-shaped firstportions 351 are joined by second portions 352 and surroundparallelogram-shaped apertures 360. Under an applied tension (orcompression), first portions 351 may rotate, paths betweennon-neighboring second portions 352 may become more straight (or lessstraight), and auxetic element 330 may exhibit an outward expansion (orinward contraction) in two orthogonal directions.

More generally, auxetic element 330 may have any of a variety ofconfigurations including first portions 351, which may beregularly-shaped polygons or may be irregularly-shaped; second portions352 joining first portions 351; and apertures 360, which may beregularly-shaped polygons or may be irregularly-shaped. Similarly,auxetic element 330 may have a regular geometric pattern based uponpolygonal units, or may have an irregular pattern, or no pattern at all.With or without regularly shaped portions 351 and apertures 360, andwith or without a regular geometric pattern, auxetic element 330 may beoperable to expand in two orthogonal directions under an applied tensionin only one of the directions, and may be operable to contract in twoorthogonal directions under an applied compression in only one of thedirections.

Auxetic element 330 may also have any of the configurations of theauxetic sole structures disclosed in U.S. patent application Ser. No.14/030,002, which was filed on Sep. 18, 2013 and entitled “AuxeticStructures And Footwear With Soles Having Auxetic Structures,” suchprior U.S. Patent Application being entirely incorporated herein byreference.

FIGS. 37-41 depict another configuration of footwear 10. In thisconfiguration, sole structure 300 wraps upward around lower sideportions of base layer 210. Some of first portions 351, second portions352, and apertures 360 form part of a side surface of footwear 10, andare accordingly exposed to an exterior of footwear 10 even when footwear10 is resting on the ground. This alternate configuration of solestructure 300 may advantageously assist sole structure 300 in wrappingupward along the sides of footwear 10 when an auxetic expansion isinduced in auxetic element 330, which may in turn increase the abilityof footwear 10 to dynamically adjust its fit upon a wearer's foot andkeep footwear 10 better conformed to the foot of the wearer.

In the configuration of FIGS. 37-41, footwear 10 has four tensilestrands 1230 with first ends 1231 positioned in forefoot region 11 oflateral side 15, middle portions 1233 extending around lace apertures227, and second ends 1232 positioned in forefoot region 11 of lateralside 15. Footwear 10 also has four tensile strands 2230 with first ends2231 positioned in midfoot region 12 of medial side 14, middle portions2233 extending around heel region 13, and second ends 2232 positioned inheel region 13 of lateral side 15. Footwear 10 accordingly has at leasttwo sets of tensile strands: a first set arranged to extend between laceapertures 227 and forefoot region 11 on lateral side 15, and a secondset arranged to extend between midfoot region 12 on medial side 14 andheel region 13 on lateral side 15.

This alternate configuration of tensile strands provides an upper boundto the expansion of portions of upper 200 that extend between laceapertures 227 on lateral side 15 and auxetic element 330 in forefootregion 11 of lateral side 15. Similarly, this configuration of tensilestrands also provides an upper bound to the expansion of portions ofupper 200 that extend from auxetic element 330 in midfoot region 12 ofmedial side 14, to lace apertures 227 on medial side 14, around heelregion 13, and to auxetic element 330 in heel region 13 of lateral side15.

Footwear 10 may thus include tensile strands 1230 having first ends 1231and second ends 1232 positioned in the same region and side of thefootwear, and footwear 10 may also include tensile strands 2230 havingfirst ends 2231 positioned on medial side 14, and second ends 2232positioned on lateral side 15. More generally, footwear 10 in variousconfigurations may include tensile strands 230 having first ends 231positioned in any region and on either side of the footwear, and secondends 232 positioned in any region and on either side of the footwear.

While various embodiments have been described, the description isintended to be exemplary, rather than limiting and it will be apparentto those of ordinary skill in the art that many more embodiments andimplementations are possible that are within the scope of theembodiments. Accordingly, the embodiments are not to be restrictedexcept in light of the attached claims and their equivalents. Also,various modifications and changes may be made within the scope of theattached claims.

What is claimed is:
 1. An article of footwear comprising: an upper and asole structure, the sole structure comprising: an upper surface and anopposing ground-contacting surface, the upper abutting and coupled withthe upper surface; a plurality of apertures extending from at least oneof the upper surface or the ground-contacting surface, the solestructure further including a plurality of sole portions disposedbetween adjacent ones of the plurality of apertures, wherein thearrangement of the plurality of sole portions and the plurality ofapertures forms an auxetic structure; and the upper comprising: a baselayer and a tensile strand, the tensile strand having a first end and asecond end, a portion of the tensile strand between the first end andthe second end being separate from the material of the base layer andlying adjacent to a surface of the base layer; and wherein the first endof the tensile strand has a fixed position relative to a peripheralregion of the sole structure: and wherein a tension applied through thetensile strand induces an auxetic deformation of the sole structure suchthat each of the plurality of apertures expands simultaneously in boththe radial and longitudinal directions.
 2. The article of footwear ofclaim 1, wherein the base layer exhibits a first degree of expansionunder the applied tension, and the first end of the tensile strandexhibits a second degree of expansion under the applied tension, andwherein the first degree of expansion is greater than the second degreeof expansion.
 3. The article of footwear of claim
 1. wherein the firstend of the tensile strand is secured to the peripheral region of thesole structure.
 4. The article of footwear of claim 1, wherein thesecond end of the tensile strand is secured to a middle region of thebase layer.
 5. The article of footwear of claim 1, wherein the secondend of the tensile strand is secured to a lace aperture region of thebase layer.
 6. The article of footwear of claim 1, wherein the first endof the tensile strand is secured to the peripheral region of the solestructure at a first location, and the second end of the tensile strandis secured to the peripheral region of the sole structure at a secondlocation.
 7. The article of footwear of claim 1, wherein the base layerincludes a lace aperture, and a middle portion of the tensile strandextends around the lace aperture.
 8. The article of footwear of claim 1,wherein the plurality of sole portions includes a plurality of firstportions and a plurality of second portions, the first portions beingjoined to each other by the second portions, the first portions and thesecond portions defining the plurality of apertures, and the firstportions being operable to locally rotate relative to each other andwithin the sole structure in response to a tension applied across aportion of the sole structure.
 9. An article of footwear comprising: asole structure including: an upper surface and an opposingground-contacting surface; a plurality of apertures extending from atleast one of the upper surface or the ground-contacting surface, thesole structure further including a plurality of sole portions disposedbetween adjacent ones of the plurality of apertures, wherein thearrangement of the plurality of sole portions and the plurality ofapertures forms an auxetic structure; a base layer secured to aperipheral region of the sole structure; and a tensile strand separatefrom the material of the base layer, the tensile strand having at leastone end fixed in position relative to a peripheral region of the solestructures; and wherein a tension applied through the tensile strandinduces an auxetic deformation of the sole structure such that each ofthe plurality of apertures expands simultaneously in both the radial andlongitudinal directions.
 10. The article of footwear of claim 9, whereinthe tensile strand has at least one end secured to the peripheral regionof the sole structure.
 11. The article of footwear of claim 9, whereinthe tensile strand has another end secured to one of a middle region ofthe base layer and a lace aperture region of the base layer.
 12. Thearticle of footwear of claim 9, wherein the tensile strand has two endsfixed in position relative to the peripheral region of the solestructure.
 13. The article of footwear of claim 12, wherein the baselayer includes a lace aperture, and a middle portion of the tensilestrand extends around the lace aperture.
 14. The article of footwear ofclaim 9, wherein the footwear comprises a plurality of tensile strandsand the base layer has a plurality of lace apertures, each of thetensile strands extending from a peripheral region of the sole structureto an area proximal to a lace aperture.
 15. The article of footwear ofclaim 1, wherein the auxetic deformation of the sole structure isgreater at the ground-contacting surface than at the upper surface ofthe sole structure.
 16. The article of footwear of claim 9, wherein theauxetic deformation of the sole structure is greater at theground-contacting surface than at the upper surface of the solestructure.